Packer described the lecture as a discussion on “what we have learned, where it is important for treating patients, and where there are questions”, and said the data in CABANA were “explanatory, not just exploratory”.
CABANA (Catheter ablation versus antiarrhythmic drug therapy for atrial fibrillation) was an investigator-initiated, open-label, multicentre, randomised trial in 126 centres in 10 countries of 2,204 symptomatic patients with new onset or undertreated atrial fibrillation aged ≥65 years, or <65 years with ≥one risk factors for stroke. The findings were published in March 2019.
The catheter ablation group (n=1108) underwent pulmonary vein isolation, and the drug therapy group (n=1096) received standard rhythm and/or rate control drugs, according to guidelines. The primary endpoint for the analysis of mortality and cardiovascular events was a composite of death, disabling stroke, serious bleeding, or cardiac arrest. Three of the 13 prespecified secondary endpoints were reported—all-cause mortality, total mortality or cardiovascular hospitalisation, and recurrence of atrial fibrillation.
The study found that catheter ablation for AF leads to a reduction in atrial fibrillation, better quality of life, and lower hospitalisations than medical therapy, but does not significantly reduce the risk of death, disabling stroke, serious bleeding, or cardiac arrest.
In his presentation Packer, who was the lead investigator for CABANA, assessed the impact of different aspects of the findings, “putting all the evidence together”.
On recurrence of atrial fibrillation (AF), he said: “Patients who were ablated had a significantly better freedom from recurrence over time. Drug therapy patients had more of a problem and had more recurrences overall.” Similarly, quality of life, measured by the Mayo AF specific symptom inventory (MAFSI) scoring system: “The quality of life issues or the symptomatic problems were much less in ablated patients. It is more of an issue in those patients who were treated with drugs. This went out to 16 months.”
He also examined age, AF type (paroxysmal, or persistent, or long standing persistent), heart failure, minorities, the impact of normal sinus rhythm, and differences in four-year event rates between North America and Europe, Asia, Russia and Australia.
Looking at reverse remodelling, Packer cited a paper that is due to be published shortly showing that “the patients who were ablated had a greater reduction in pulmonary veins and had a greater reduction in left atrial volume index”. He also revealed that work is ongoing to look at pattern of progression, burden, complications, and symptoms and impact of atrial fibrillation, and the components that go into each factor.
“We are going to make a composite score, kind of like a CHAD VASC score, … to be utilised for giving a better sense of how a patient’s atrial fibrillation is doing, whether it is with ablation or not, so that we totally get rid of the 30 second endpoint that we have used and we have all hated so much.”
And he predicted: “We are going to have to change the endpoints and the recommendations in catheter ablation. Symptomatic paroxysmal atrial fibrillation has always been a IA but we think that persistent atrial fibrillation will be a IA or B. The other thing that changes is use for first-line therapy, where it will shift to a IA based on CABANA, and probably EAST [Early treatment of atrial fibrillation for stroke prevention trial], but we will have to wait for those outcomes. And then if you look at patients with heart failure with reduced ejection fraction, that will likely become a IIA or a IIB.”